Lawyers for the Marshalls say they won't give up in what is seen as a David and Goliath type challenge to the world's nuclear powers.

Lawyers in the US have formally filed a Notice of Appeal after the case against Washington was dismissed on constitutional grounds by a US Federal District Court in February.

The Marshalls' Foreign Minister Tony de Brum says the country will use every legal avenue to make sure what's known as the Nuclear Zero Lawsuit is achieved in his lifetime.

The Marshall Islands which was used as a testing ground for the United States' nuclear programme in the forties and fifties claims the US and other nuclear powers are in breach of the 1968 Non-Proliferation Treaty by failing to negotiate for nuclear disarmament.

The Marshall Islands still has cases pending against Britain, India and Pakistan at the International Court of Justice in The Hague.